It is very difficult to comprehend the behaviors of bluefin tuna, bigeye tuna, and other migratory fish that migrate extensively through the oceans. In order to estimate the distribution of such highly migratory fish, satellite data are used to grasp the marine environment, which affecting on fish migration.
A good fishing ground prediction information service method is known in which good catch pattern images are extracted, according to the seasons, fishing ground zones, fish species, from the past sea surface temperature images that are originated from satellite images and corresponding fishing ground information at the time of good catch, and fishing ground are predicted from an up-to-date sea surface temperature chart and fishing ground information and delivered to fishing sites (see Japanese Patent Application Laid-Open No. 2004-192231).
Further, a water temperature chart preparing method is proposed in Japanese Patent Application Laid-Open No. 2001-283189. In order to facilitate a fishing boat to utilize accurate water temperature values, a composite image without clouds is prepared from a satellite image, a base image is set as a cloud-zone reference image, and a cloud-zone identification image is generated by comparing all pixel values in a predetermined region for water temperature data with all pixel values in regions of the cloud-zone reference image. A cloudless image is prepared by removing cloud zones, and the pixel values in the cloud-zone reference image are implanted in the removed cloud zones. A complemented image is generated by complementing the pixel values in the cloud zones using the implanted pixel values and pixel values around the cloud zones while correcting the implanted pixel values.
Since the conventional fishing ground prediction method described above is based on sea surface temperature measured by satellites, it cannot clarify temperature distributions of three dimensional thermal structure of the ocean where fish inhabits. As a consequence, previous methods are reliable to predict good fishing ground.